SIRCarrierState {EpiDynamics}

SIR model with carrier state (2.7).

Description

Solves a SIR model with carrier state.

Usage

SIRCarrierState(pars = NULL, init = NULL, time = NULL, ...)

Arguments

pars

vector with 6 values: the per capita death, transmission, infectious-recovery and carrier-recovery rates, the proportion of reduction in transmission from carriers compared with infectious and the proportion of infectious that become carriers. The names of these values must be "mu", beta", "gamma", "Gamma", "epsilon" and "rho", respectively.

init

vector with 4 values: the initial proportion of proportion of susceptibles, infectious, carriers and recovered. The names of these values must be "S", "I", "C" and "R", respectively.

time

time sequence for which output is wanted; the first value of times must be the initial time.

...

further arguments passed to ode function.

Details

This is the R version of program 2.7 from page 44 of "Modeling Infectious Disease in humans and animals" by Keeling & Rohani.

All parameters must be positive and S + I + C + R <= 1.

Value

list. The first element, *$model, is the model function. The second, third and fourth elements are the vectors (*$pars, *$init, *$time, containing the pars, init and time arguments of the function. The fifth element *$results is a data.frame with up to as many rows as elements in time. First column contains the time. Second to fifth column contain the proportion of susceptibles, infectious, cariers and recovered.

References

Keeling, Matt J., and Pejman Rohani. Modeling infectious diseases in humans and animals. Princeton University Press, 2008.

See Also

ode.

Examples

# Parameters and initial conditions.
parameters <- c(mu = 1 / (50 * 365), beta = 0.2, 
                    gamma = 0.1, Gamma = 0.001, 
                    epsilon = 0.1, rho = 0.4)
initials <- c(S = 0.1, I = 1e-4, C = 1e-3, R = 1 - 0.1 - 1e-4 - 1e-3)

# Solve the system.
sir.carrier.state <- SIRCarrierState(pars = parameters,
                                     init = initials, time = 0:60)
PlotMods(sir.carrier.state)